Scientists hope radiotherapy breakthroughs will transform cancer treatment

Scientists hope that breakthroughs at the National Physical Laboratory (NPL) will transform cancer treatment in the UK and across the world.

The experts have developed a range of projects that significantly improve the accuracy of a type of radiotherapy treatment called proton beam radiotherapy.

This therapy can more precisely target tumours without damaging surrounding healthy tissue, minimising the side effects of radiotherapy – particularly in children – such as heart failure, pulmonary fibrosis, and secondary cancer.

Unlike traditional radiotherapy, the radiation from proton beam radiotherapy can be confined largely to the tumour, minimising the damage to surrounding healthy tissue.

However, in order to make the most of the treatment, the accuracy of the radiation dose from proton beam treatment must be similar to that achieved using existing radiotherapy treatments.

To address this, the team at NPL have made what they describe as three important breakthroughs.

They have been able to produce their own highly accurate tool for measurement and assuring radiation dosage amounts called the Primary Standard Proton Calorimeter (PSPC).

The researchers have also developed new plastic materials to precisely imitate human tissue such as bone and muscle during testing.

Thirdly, they are performing pioneering measurements to demonstrate a new form of radiotherapy called Flash RT.

The treatment is as effective as current techniques but also prevents unnecessary damage to healthy tissue.

According to the scientists, Flash can shorten the time that paediatric patients must spend in the hospital.

Flash treatments can be delivered in fewer or even single deliveries in comparison to conventional radiotherapy which is often delivered in fractions over a period of about six weeks with the patient needing to attend hospital every day.

Accurate dosimetry – the calculation of absorbed dose and optimisation of dose delivery in radiation therapy – is essential to avoid errors that might result in a patient receiving an incorrect dose of radiation and less chance of successful treatment.

Currently, any form of radiotherapy results in unwanted but unavoidable deposition of radiation to healthy tissue around the targeted tumour.

Studies have shown that treatment using ultra-high dose rate (UHDR) radiation could significantly spare healthy tissue while also being at least as effective as treatments at conventional dose rates in controlling the tumour – this is known as “the Flash effect”.

Hannah Cook, a higher scientist at NPL, said: “Proton therapy dosimetry and audit development is very interesting and rewarding research.

“The aim of our work is to provide confidence to clinical centres offering proton therapy treatment within the UK and worldwide, with the hope to further improve cancer patient outcome.”

NPL science area leader Russell Thomas told the PA news agency proton beam therapy has been around since the 1940s, but only around 300,000 patients around the world have been treated with it.

In comparison, some 160,000 patients a year are treated with conventional photon therapy in the UK, he added.

Mr Thomas explained that in the past one of the blocks to photon beam therapy has been cost.

A proton beam machine can cost in the region of £225 million, compared to just a couple of million pounds for a conventional machine.

There are currently only two proton beam therapy centres in the UK – at The Christie NHS Foundation Trust in Manchester, or University College London Hospitals NHS Foundation Trust.

Mr Thomas told PA that he hoped that one day there would be enough centres in the UK to treat the numbers of patients who might benefit.

He added: “I think with proton provision in the UK now we’re probably treating slightly less than 2% of the radiotherapy population that would benefit – 5% to 20% is the estimate.

“So I’d like us to at least get to 5% of treatments.

“I think what I’d also like to see is investment for you, and ways of looking at other particles and other ion therapy.

“Different types of radiation and beam and a radiation treatment will have different radio biological effectiveness.

“It would be great if we could have some funding in the UK to explore these at the radio biological level, at the pre-clinical level so that we can work out right, well this would be good if we could follow this type of particle and we can start building this type of machine for treating patients.”

Ana Lourenco, senior scientist at NPL, said: “We are working with the Institute of Physics and Engineering in Medicine (IPEM) in developing a new Code of Practice (CoP) for reference dosimetry of proton beams.

“The upcoming IPEM CoP, will utilise the NPL PSPC, and provide a direct absorbed dose to water calibration service for proton therapy beams.

“This significant development will reduce uncertainty in dose delivery, ensuring optimal tumour control and improved accuracy in proton therapy treatments.

“The establishment of consistent standards supported by the CoP will not only benefit patients within and between treatment facilities but also lay the foundation for the development of clinical trials in proton therapy.”